Search results for "water stre"

Detecting crop irrigation status in orchard canopies with airborne and ASTER thermal imagery

2007

This work provides a description of the research conducted to assess if ASTER satellite data enable the detection of the water status in orchard tree crops. Summer and winter TERRA-ASTER images were acquired over a study area of Seville in southern Spain over a 6-year period. 1076 olive orchards were monitored in this area, obtaining field location, area, tree density, and irrigation status information. Surface temperature images were obtained using the TES method and 0.5 m resolution panchromatic ortho-rectified imagery collected over the entire area to obtain vegetation cover. A comparison study of the temperature difference between orchards under different irrigation schemes is presented…

The Indian-French Trishna Mission: Earth Observation in the Thermal Infrared with High Spatio-Temporal Resolution

2018

International audience; The monitoring of the water cycle at the Earth surface which tightly interacts with the climate change processes as well as a number of practical applications (agriculture, soil and water quality assessment, irrigation and water resource management, etc...) requires surface temperature measurements at local scale. Such is the goal of the Indian-French high spatio-temporal TRISHNA mission (Thermal infraRed Imaging Satellite for High-resolution Natural resource Assessment). The scientific objectives of the mission and research work conducted to consolidate the mission specifications are presented. Progress in modelling of surface fluxes is then discussed. The main spec…

Evaluation of the LSA-SAF gross primary production product derived from SEVIRI/MSG data (MGPP)

2020

The objective of this study is to describe a completely new 10-day gross primary production (GPP) product (MGPP LSA-411) based on data from the geostationary SEVIRI/MSG satellite within the LSA SAF (Land Surface Analysis SAF) as part of the SAF (Satellite Application Facility) network of EUMETSAT. The methodology relies on the Monteith approach. It considers that GPP is proportional to the absorbed photosynthetically active radiation APAR and the proportionality factor is known as the light use efficiency ε. A parameterization of this factor is proposed as the product of a εmax, corresponding to the canopy functioning under optimal conditions, and a coefficient quantifying the reduction of …

ECOHYDROLOGICAL MODELLING IN MEDITERRANEAN AREAS AND WETLANDS

2010

La seguente dissertazione verte sul campo di ricerca noto come Ecoidrologia. Sebbene tale scienza, che studia le mutue interazioni fra ciclo idrologico e gli ecosistemi naturali, sia stata recentemente oggetto di svariati studi, alcuni dei suoi numerosi aspetti rimangono tuttavia ancora alquanto inesplorati. L’obiettivo principale della presente tesi è quello di rivisitare la letteratura scientifica esistente sull’argomento, cercando di adattare concetti e modelli sviluppati per certi ecosistemi anche alle peculiarità di altri ambienti meno studiati, come quelli aridi e semiaridi tipici della zona Mediterranea o le cosiddette “wetlands”, zone umide e paludose. In particolare, viene approfon…

Adapting FAO-56 Spreadsheet Program to estimate olive orchard transpiration fluxes under soil water stress condition

2012

A carbon budget model to predict branch carbohydrate deficiencies as a function of water stress and crop load in pistachio (Pistacia veraL.)

2018

The effect of irrigation and crop load on alternate bearing was studied in pistachio tree using a “branch carbon budget model” developed to calculate branch carbohydrate balance. Experiences were conducted in Sicily (37°26’N, 14°03’E, 360 m a.s.l.) on female trees of ‘Bianca’. Two treatments were applied: rainfed (T0) and 100 mm of irrigation (T100). At 29, 44, 65, 86, 103 and 121 DAFB, on one fully expanded leaf selected on three trees per treatment, were monitored leaf gas exchanges. At 15 days interval, three branches treatment-1 were excised and, in the lab, the following parameters were measured: total photosynthetically active leaf surface; number of leaves, fruits, shoot fresh weight…

Improvement of FAO-56 Model to Estimate Transpiration Fluxes of Drought Tolerant Crops under Soil Water Deficit: Application for Olive Groves

2014

[EN] Agro-hydrological models are considered an economic and simple tool for quantifying crop water requirements. In the last two decades, agro-hydrological physically based models have been developed to simulate mass and energy exchange processes in the soil-plant-atmosphere system. Although very reliable, because of the high number of required variables, simplified models have been proposed to quantify crop water consumes. The main aim of this paper is to propose an amendment of the Food and Agricultural Organization (FAO) of the United Nations FAO-56 spreadsheet program to introduce a more realistic shape of the stress function, valid for mature olive orchards (Olea europaea L.). The mod…

Mass and surface energy balance approaches for monitoring water stress in vineyards

2013

Abstract Tree crops are representing one of most widespread agricultural systems in Mediterranean regions, thus contributing in a substantial way to the economy and productivity of primary sectors of the countries interested. Besides the aspects concerning their economical relevance, tree crops like vineyards, olive and orange orchards are also typical elements of the Mediterranean landscape, and their ecological role has been recently revitalised in consideration of their function as carbon sinks for the Kyoto agreement. The environmental and economical sustainability of these agricultural systems in arid and semi-arid zones has to cope with the availability and management of water resourc…

Climate changes' effects on vegetation water stress in Mediterranean areas

2010

Many recent studies have demonstrated that CO(2) increase is driving the climate in Mediterranean areas towards important changes, mainly represented by a temperature increase and a contemporaneous rainfall reduction. Starting from this premise, the primary aim of the present study is to investigate the effects of potential climatic changes on vegetational stress in Mediterranean ecosystems. Particular attention is here focussed only on the plants' water stress in water controlled ecosystems, mainly related to soil water balance. The interactions among climate, soil and vegetation are evaluated numerically by means of an ecohydrological model. In this work, different future climatic scenari…

Combined use of eddy covariance and sap flow techniques for partition of ET fluxes and water stress assessment in an irrigated olive orchard

2013

Correct estimation of crop actual transpiration plays a key-role in precision irrigation scheduling, since crop growth and yield are associated to the water passing through the crop. Objective of the work was to assess how the combined use of micro-meteorological techniques (eddy covariance, EC) and physiological measurements (sap flow, SF) allows a better comprehension of the processes involving in the Soil–Plant–Atmosphere continuum. To this aim, an experimental dataset of actual evapotranspiration, plant transpiration, and soil water content measurements was collected in an olive orchard during the midseason phenological period of 2009 and 2010. It was demonstrated that the joint use of …